Meaning of “on top of sth” - Learner’s Dictionary

on top of sth

B2 in addition to something else that is bad:

And then, on top of everything else, her car was stolen.

able to deal with or in control of something:

I'm not at all sure that he's on top of the situation.

(Definition of “on top of sth” from the Cambridge Learner’s Dictionary © Cambridge University Press)